Company of U.S. Marines on a tactical sweep during the Vietnam War.

Activities of "F" Company, 2nd Battalion, 9th Marine Regiment, during Operation Thor , in the Vietnam War. They are engaged in a sweep, near Xuan Hai,, 1800 meters below the DMZ. U.S. Marines wearing utilities, cart belts, bulletproof vests, camouflaged helmets and carrying canteens and M-16 rifles cross a grassy area. A marine carries a PRC-25 radio on his back crawls through the grassy area.. Battalion Command post set up in the field with communications gear and tall antennas. M-48 tanks.. A marine takes cover in a shallow hole. Grass in the foreground. The marines stand, walk and sit. One marine holds a phone radio to his ear and walks out. Second marine lying on the ground. One of them wearing a PRC-25 radio on his back holds the handset of the radio to his ear. Other radio operators kneel in the background. A radio operator lying on ground places the phone of the radio to his ear, then speaks and looks out. The radio operator smokes a cigarette while kneeling. The marines kneel near the skeleton of a tree. A marine with an M-16 rifle at the ready seated on the ground. A radio operator drinks from his plastic canteen. Group of marines with M-16 rifles ride atop an M67A3 flame-thrower tank moving across the bushy area. Tank crewman in hatch. The vehicle turns and moves out. Smoke rises from an area in the background. A marine radio operator lying on the ground holding the handset of a radio makes a note on his camouflaged helmet laying next to him.